The present invention relates to electrical machines which convert mechanical energy into electrical energy, or vice versa, by an interaction between a magnetic field and an electric current. In particular, the present invention relates to a casing for such an electric machine, a rotor for such an electric machine, a conductive element of a rotor winding for such an electric machine, and a method of forming such a conductive element. Examples of such electric machines are electric motors, dynamos and alternators.
In known electric machines, the assembly of a rotor winding may be time consuming and therefore expensive. Moreover the rotor winding often comprises a large number of different parts, which increases the overall cost of the electric machine.
The performance of such electric machines may also be limited by the amount of heat generated in the rotor winding and in the region of the commutator. As a result of this limited performance, the range of applications of such electric machines, particularly in electrically powered vehicles, has been restricted.